I'm not in favor of laws requiring guns be kept locked up because in general I don't like government intrusion at that level, it's not applied to other areas of life, etc.

But I do think there is a social responsibility in not doing something stupid. A glass gun cabinet next to the front door is just asking for someone to steal your guns. If someone steals my TV, I file an insurance claim and get a new TV. If someone steals my guns, they could do grave harm with them. That wouldn't make it my fault, but I feel a little nobler if I keep them as protected from theft/misuse as is reasonably possible.

I lock up my guns so (a) they don't get stolen, (b) there is no unauthorized access (kids), and (c) they have a good chance of staying unharmed in the event of a fire.

The city I live in does have a law that does make parents responsible if children misuse a firearm. I have no problem with that.